Polybutene containing soluble oils

ABSTRACT

Soluble oils are disclosed which contain, as the principal component, polybutene of 200-500 molecular weight. Also present are an organic dispersant and a C18 straight-chain carboxylic acid salt.

United States Patent Olund Feb. 8, 1972 [54] POLYBUTENE CONTAININGSOLUBLE OILS [72] Inventor:

[73] Assignee:

Sven A. Olund, San Rafael, Calif.

Cheveron Research Company, San Francisco, Calif.

[22] Filed: Jan. 27, 1969 [21] Appl.No.: 794,368

2,744,870 5/1956 Stillebroeretal. ..252/35 Francis et al. ..252/33.2Fisher ....252/33.2

2,920,718 1/ 1960 Howell et a1.... ..252/40 3,019,187 1/1962 Panzer etal. ..252/33.2 3,132,104 5/1964 Scherer ..252/59 3,298,951 1/ 1967Guminski. ....252/52 3,298,954 l/1967 Brown ....252/56 3,396,108 8/1968Caruso ..252/18 Primary Examiner-Daniel F. Wyman Assistant Examiner-l.Vaughn Attorney-A. L. Snow, F. E. Johnston, B. l. Rowland and J. W.McClain [57] ABSTRACT Soluble oils are disclosed which contain, as theprincipal component, polybutene of 200-500 molecular weight. Alsopresent are an organic dispersant and a C straight-chain carboxylic acidsalt.

7 Claims, No Drawings POLYBUTENE CONTAINING SOLUBLE OILS BACKGROUND OFTHE INVENTION This invention relates to soluble oil compositions and inparticular to the use of polybutene as the principal component of asoluble oil composition.

Soluble oils are known in the lubrication industry as those oils which,upon mixture with water, rapidly form stable oil-inwater emulsions. (Asused herein, soluble oil refers to the oil composition itself andsoluble oil emulsion refers to the emulsion of the soluble oil inwater.) Soluble oil emulsions find numerous uses, including uses ascutting oils and hydraulic fluids. In general, they may beadvantageously used wherever a lubricating fluid is also required tofunction as a heat transfer agent. Thus, a widespread use is as cuttingoils where the action of the cutting tool on the metal surface generatesa considerable amount of heat. This heat must be rapidly dissipated ifthe life of the cutting tool is to be extended and the work surfacesprotected from marring.

Soluble oil emulsions also have many applications where lubricatingfluids are required to be nonflammable'or substantiallyflarne-resistant. The soluble oil itself may be a hydrocarbon and have agreater or lesser degree of flammability; however, in use as an emulsionwith the water, most soluble oils become substantially nonflammable.These emulsions thus find widespread use in such applications asfire-resistant hydraulic fluids.

SUMMARY OF THE INVENTION This invention is a soluble oil which has acomposition comprising 70-90 parts by weight polybutene, where thepolybutene has a number average molecular weight of 200-500, 8-15 partsby weight of an organic dispersant, such as a mahogany sulfonate salt,and, in addition, 0.2-3 parts by weight of a 18 straight-chaincarboxylic acid salt.

DETAILED DESCRIPTION OF THE INVENTION In its broadcast form, the solubleoil composition claimed herein comprises 75-90 parts by weightpolybutene, where the polybutene has a number average molecular weightof 200-500, and 8-15 parts by weight of organic dispersant and, inaddition, 0.2-3 by weight of C straight-chain carboxylic acid salt. Insome preferred embodiments, the polybutene number average molecularweight is 300-450 and the organic dispersant is nonionic.

The principal component of the soluble oil is polybutene. The numberaverage molecular weight of the polybutene is 200-500, preferably300450. The number average molecular weight may be determined by use ofa calibrated vapor pressure osmometer. The osmometer is calibrated byusing solutions of known molecular weight solutes in benzene. A typicalcommercial osmometer is the Model 301A, manufactured by Mechrolab ofMountain View, Calif.

The soluble oil also contains 1-3 parts of C aliphatic straight-chaincarboxylic acid salt. The carboxylic acid may be saturated orunsaturated, generally having not more than two sites of ethyleneunsaturation. Illustrative carboxylic acid anions are stearate, oleate,linoleate, linolenate, or mixtures of two or more of these. The cationwill be an alkali metal. The alkali metals of atomic number below 20(lithium, sodium, and potassium) are preferred, with the most preferredbeing potassium.

The salt of the carboxylic acid may be directly incorporated into theoil as such, but it is often more convenient to form the salt in theoil. This is accomplished by adding to the oil the C straight-chaincarboxylic acid (or a mixture of the C acids) and alkali metalhydroxide. To a typical oil would be added oleic acid and potassiumhydroxide, which would react to form the desired potassium oleate.

The oil will also include 8-15 parts of at least one organic dispersant.The dispersant may be ionic or nonionic. Typical ionic dispersants arethe alkali and alkaline earth metal salts of alkyl, alkaryl, andmahogany sulfonates having l-30 carbon atoms per molecule. The mahoganysulfonates particularly include oil-soluble aromatic sulfonate saltsderived from petroleum. Many of the aromatic sulfonates have cycloalkyl(i.e., naphthenic) groups in the side chains attached to the benzenering. The industrial production of oil-soluble mahogany sulfonates frompetroleum is well understood in the art and is described in theliterature. Normally, the alkyl sulfonates require at least 20 carbonatoms for oil solubility. The alkaryl sulfonates, however, permit analkyl portion totaling only about 18 carbon atoms. To attain therequisite oil solubility, therefore, requires that the hydrocarbonportion of the sulfonate have a molecular weight between about 250 and1,000. Preferably this molecular weight is between 300 and 600.

In a preferred embodiment, the dispersant is nonionic, typicallyethoxylated alkyl phenol having 7-15 carbon atoms in the alkyl portionof the molecule and with an ethylene oxide content corresponding to20-40 percent of the overall molecular weight. With both ionic andnonionic dispersants, it is to be understood that the term dispersant"includes mixtures of two or more compatible dispersants of the typesdescribed. Other additives, such as oxidation inhibitors, rustinhibitors, and bactericides may also be present in small amounts ifthey are compatible with the other components of the soluble oil and donot adversely affect the ability of the oil to form a stable emulsionwith water. Typically, they do not exceed, in total, 2 weight percent ofthe the entire oil composition, and often are in the parts per millionrange.

The soluble oil is mixed with water to form the stable product emulsion.In general, water will be the continuous phase and oil the dispersedphase. The range of ratios of oil to water will be 1:4 to 1:100.Preferred is the range 1:10 to 1:20. The exact portion chosen willdepend on the particular application in which the product emulsion is tobe used.

The following examples will illustrate this invention. All amounts arein parts by weight.

Example 1 Soluble oil A contained 80.7 parts polybutene with thepolybutene number average molecular weight being 330. The potassiumoleate present was formed by reacting 1.6 parts of oleic acid and 0.5parts of potassium hydroxide. The sulfonate present was as 11.2 parts ofa 60 percent sodium mahogany sulfonate, having a molecular weight ofabout 400, in a naphthenic oil.

Example 2 Soluble Oil B had a composition similar to that of Soluble OilA, with the exception that the polybutene used had a number averagemolecular weight of 440.

Example 3 Soluble Oil C differed from Soluble oils A and B in that ithad a nonionic emulsifier. Soluble Oil C contained 88.4 parts of the 330molecular weight polybutene. Potassium oleate was produced in the oil byreacting 0.3 parts potassium hydroxide with 1.3 parts oleic acid. Thenonionic dispersant was present as 10.0 parts of an ethoxylated nonylphenol with an ethylene oxide content of about 35 percent of the totalmolecular weight.

The following table will illustrate the advantages of the polybutenesoluble oil emulsions of this invention over conventional solubleemulsions of the prior art, as represented by a leading commercialhydrocarbon soluble oil.

The soluble oils of this invention were tested in a drilltorque test ofthe type described by Stokeley in Lubrication Engineering, Vol. 9, No.3, p. 137 (June, 1953). In this test a series of l-inch deep holes aredrilled with a precision-sharpened drill into stainless steel blocks ata constant drilling rate. The drill speed is increased by 50 r.p.m. foreach successive hole. The torque on the drill while drilling each holeis measured. Failure of the drill is defined to occur where the torquerequired to drill the hole is inch-pounds or greater.

In the drill-torque test, the emulsions of the better soluble oilstested will be indicated by producing less torque at a given drill speedand by producing drill failure at a higher drill speed than do thepoorer soluble oils. The data of the following table were obtained withthe aforementioned commercial hydrocarbon soluble oil and soluble oilsA, B, and C, each in an emulsion of 1 part oil to parts water (byvolume).

TABLE Drill Torque, in.-lbs. Drill Speed It is evident from the abovetable that the soluble oils of this invention (Oils A, B, and C) arecomparable to the commercial oil at the lowest drill speed andsignificantly better than the commercial oil at all higher speeds.Further, the oils of this invention permit operation at higher drillspeeds without failure. It is also evident that oil containing thenonionic dispersant, Oil C, is preferred because it permits the highestdrill speed without failure.

I claim:

1. A soluble oil comprising 75-90 parts by weight polybutene, saidpolybutene having a number average molecular weight of 200-500, 8-15parts by weight of an organic dispersant, and, in addition, 0.2-3 partsby weight of C straightchain carboxylic acid salt of alkali metal.

2. The soluble oil described in claim 1 wherein said polybutene averagemolecular weight is in the range of 300-450.

3. The soluble oil described in claim 1, wherein said dispersant is atleast one alkali or alkaline earth metal salt of an alkyl, alkaryl, ormahogany sulfonate having 10-30 carbon atoms per molecule.

4. The soluble oil described in claim 1, wherein said dispersant isnonionic.

5. The soluble oil described in claim 4, wherein said nonionicdispersant is an ethoxylated alkyl phenol having 7-15 carbon atoms inthe alkyl portion of the molecule.

6. The soluble oil described in claim 1, wherein said acid salt is anoleate.

7. The soluble oil described in claim 6, wherein said acid salt ispotassium oleate.

2. The soluble oil described in claim 1 wherein said polybutene averagemolecular weight is in the range of 300-
 450. 3. The soluble oildescribed in claim 1, wherein said dispersant is at least one alkali oralkaline earth metal salt of an alkyl, alkaryl, or mahogany sulfonatehaving 10- 30 carbon atoms per molecule.
 4. The soluble oil described inclaim 1, wherein said dispersant is nonionic.
 5. The soluble oildescribed in claim 4, wherein said nonionic dispersant is an ethoxylatedalkyl phenol having 7- 15 carbon atoms in the alkyl portion of themolecule.
 6. The soluble oil described in claim 1, wherein said acidsalt is an oleate.
 7. The soluble oil described in claim 6, wherein saidacid salt is potassium oleate.